LONDON AND PARIS — Britain's position as the leading European power in NATO is in jeopardy following its exit from the European Union, potentially affecting the alliance's command structure, according to one of the UK's leading defense think tanks.

The substantive consequences of any changes to NATO's command structure are likely to be relatively limited, but Malcolm Chalmers, the deputy director general at the Royal United Services Institute (RUSI) in London, said in a Jan. 9 report that "the fact that [the consequences] are already being raised is a clear message that the UK's role and influence within NATO cannot be entirely ring-fenced from the consequences of Brexit."

Brexit refers to the UK's exit from the European Union following a national vote in June 2016.

The briefing on Britain's post-Brexit foreign and security policy said there was already some discussion of the possibility that the position of deputy supreme allied commander Europe (DSACEUR), which the UK has held since 1951, might have to be transferred to an alliance member from inside the European Union.

A British Ministry of Defence spokesman dismissed the idea of the country relinquishing its NATO command role.

"We will continue to play a leading role in European security. This includes providing NATO's deputy supreme allied commander for Europe," he said.

Britain has been among NATO's staunchest supporters for decades and is the only major power in Europe to meet the alliance's target of spending 2 percent of gross domestic product on defense.

The incoming Trump administration has warned European nations they must improve defense spending if they want continued US support in NATO.

British Army Gen. Adrian Bradshaw currently holds the DSACEUR post but is set to hand over the role to Lt. Gen. James Everard later this year.

Chalmers offered an alternative means of handling the command issue. "A second DSACEUR position could be recreated (Germany held this position until 1993), or the UK could swap its current position for the important role of Chief of Staff," he said.

The Times newspaper here reported that an unofficial French delegation had already visited Washington last year in a move aimed at convincing US officials of their credentials to become America’s leading ally in Europe after the UK leaves the EU.

One leading French analyst reckoned that questioning the UK’s hold on the No. 2 post at NATO is valid, but even if France were to accede to that position, it is far from Paris stepping up to a special relationship with Washington.

"There is an understandable and judicious question to be asked about Britain’s holding on to DSACEUR ([deputy] supreme allied command[er] Europe) as that post-holder represents Europe," said Jean-Pierre Maulny, deputy director of the French think tank Institut de Relations Internationales et Stratégiques.

Britain Defense Minister Michael Fallon (L) talks with US Defense Minister Ashton Carter (R) during a Defense ministers meeting at the NATO headquarters in Brussels on October 8, 2015. AFP PHOTO/JOHN THYS (Photo credit should read JOHN THYS/AFP/Getty Images)
Britain Defense Minister Michael Fallon (L) talks with US Defense Minister Ashton Carter (R) during a Defense ministers meeting at the NATO headquarters in Brussels on October 8, 2015. AFP PHOTO/JOHN THYS (Photo credit should read JOHN THYS/AFP/Getty Images)

British Defense Minister Michael Fallon, left, talks with US Defense Minister Ash Carter at the NATO headquarters in Brussels. France does not have a special relationship with the US like that of the UK, says a defense policy expert, who believes that isn't going to change.

Photo Credit: John Thys/AFP via Getty Images

As the UK is leaving the EU, there is a case to be made for France to take up the NATO post given Paris’ claim as the strongest EU military power, he said.

But France does not have a special relationship with the US, and that is not going to change, Maulny said.

Paris has played an active military role in Africa, which Washington has appreciated, but that does not lead to forging a special relationship, according to the analyst.

The French Defense and Foreign Affairs ministries were not immediately available for comment.

Ever since Britain voted to leave the EU, France has pushed to forge an active European defense policy alongside Germany and Italy, working through the EU. So far the agreements reached have been related to tighter border control in response to immigration flows, rather than military cooperation.

British influence on the European security agenda will, however, remain considerable, given its position as NATO's most capable and willing European power, said the analyst.

The RUSI report out of London said the UK should aim to create a new post-Brexit "special relationship" with the EU on foreign and security policy, allowing joint initiatives with the EU and action on issues of common concern.

But whatever happens with the EU, Chalmers reckons that Britain’s links with Washington will remain strong.

"Despite Trump’s election as president, the UK’s relationship with the US is likely to remain exceptionally strong in relation to nuclear and intelligence cooperation, grounded in strong mutual interest and respect developed over decades," Chalmers said.

The analyst warned, though, against a British government, isolated in Europe, becoming embroiled too closely with future US military aims, not least during the Trump presidency.

"A degree of caution may have to be exercised to maintain the UK’s freedom of action in relation to future US military campaigns. The prospect of diplomatic isolation in Europe could tempt a future government to place greater emphasis on the need to stand ‘shoulder to shoulder’ with the US in a future military conflict. Yet successive experiences during the past decades, most clearly in the decision to invade Iraq in 2003, have reinforced the need for caution. A Trump presidency could further increase the desirability of maintaining strategy autonomy," he said.